Tall speargrasses

SCIENTIFIC NAME: Austrostipa bigeniculata and A. rudis (formerly Stipa bigeniculata and S. rudis)

CATEGORY: C3 perennial

IDENTIFICATION TIPS

  • Erect, yearlong green, perennial, grasses, growing in dense clumps to 1.5m high
  • Leaves tufted at the base; long and narrow, smooth and rather stiff
  • Seedhead is a somewhat-narrow open panicle to 25-50cm long
  • Large spikelets have a single seed, with an awn (4.5-9cm long) that is abruptly twice-bent
  • Flowers from late spring to mid summer

CLIMATIC SOIL REQUIREMENTS

  • Largely confined to higher altitudes
  • Found on a range of soil types, from low fertility course sedimentary soils (granite/sandstone) to heavier, more fertile basalts. However, the presence of remnant grassland is probably more important than soil type

GRAZING NUTRITIONAL VALUE

  • Low to moderate grazing value
  • No digestibility or crude protein figures are available

MANAGEMENT STRATEGIES

  • Fairly coarse and not readily eaten until more palatable species have been grazed. More readily grazed by cattle than sheep
  • Seeds freely and can quickly recolonise disturbed site and degraded pastures
  • Seeds can cause injury to stock, especially sheep
  • Responds to fertility, but usually not fertilised due to its occurrence in remnant grasslands
  • Best suited to lightly stocked situations. Resting at flowering will aid persistence at higher stocking rates
  • Heavy grazing or slashing at flowering will reduce seed contamination, but may reduce the populations over time

SIMILAR PLANTS

  • Tall speargrass (Austrostipa bigeniculata) grows to 1.2m tall and has an awn 4-5.5cm long. It is found on a range of soils types, but is most common on heavier, more fertile soils. Of moderate grazing value, it seems to be one of the most persistent grasses in areas of African lovegrass (Eragrostis curvula) infestations
  • Tall speargrass (Austrostipa rudis) grows to 1.5m tall and has an awn up to 9cm long. It is found on low fertility sandstones and granites. Of low grazing value, it declines under set stocking and is largely absent from pastures unless lightly stocked
  • Chilean needle grass (Nassella neesiana) has a raised crown of tissue surrounding the base of the awn on the seed
A. bigeniculata paddock: D Eddy
A. bigeniculata plant: D Eddy
A. rudis seedhead: H Rose